“NEDC emissions testing was based on vehicles with limited equipment fitted as standard,” explains Samuel Keates, Director of Specifications at Autovista Group.

“Under the new WLTP regime, worst- and best-case cars need to be tested with their optional equipment fitted to present a clear view on more achievable driving emissions and fuel consumption for each level of specification that is offered.”

Analysis by Autovista Group into the impact of optional equipment on WLTP emissions figures found that most options in isolation do not have a major impact on CO2 emissions, rarely accounting for more than 1g/km of additional CO2.

Autovista examined the impact of options on a specific variant of a premium-brand D-segment model that is a popular choice with fleet buyers.

Depending on body style and drivetrain, the model variant has CO2 emissions ranging from 152-166g/km as measured by the WLTP test.

For example, fitting a tow bar can increase CO2 emissions by 1-2g/km because of the impact on weight and aerodynamics. A panoramic roof generates a similar effect. An increase in wheel size impacts the weight and rolling resistance of the car; fitting 18” wheels instead of 17” wheels adds about 2g/km more in CO2 emissions. Fitting run-flat tyres as an option instead of the standard tyre repair kit also increases emissions by about 1g/km. It is therefore easy to see how a combination of options can add up to make a difference to the emissions profile of a car and, in turn, its tax liability.

These changes may end up costing manufacturers dearly, as the European Commission has stated that any increase in costs must not be passed on to the consumer.

This, at a time when manufacturers are under pressure to gain approval for all their model variants so that they can register them after 1 September.

Safety challenge

Fleets need to ensure that their drivers understand the ADAS devices fitted to their vehicles to ensure that they make a positive impact on safety, says Arval.

The leasing and fleet management company says that some drivers don’t know that features such as city braking are fitted to their vehicle and have little idea how they work.

Shaun Sadlier, Head of Consultancy for Arval in the UK, said, “A large range of ADAS devices are making their way onto company cars quite quickly in all parts of the market. This is a good thing, as they can have a definite impact on the safety of drivers and other road users.

“However, because of the unobtrusive nature of many of these devices – they usually don’t make themselves known until they are needed – drivers often don’t know they are fitted or what they do.

“Certainly, most fleets can tell anecdotes about drivers who didn’t know they had city braking on their car until the moment came when the vehicle started braking for them. In one respect this is fine, because the technology is working, but it is also really a failure of education.

Premium brands typically have more optional extras than vehicles from the volume manufacturers and so could be more adversely affected. Conversely, Japanese and Korean OEMs could stand to benefit as their strategy has typically been to compete by offering higher levels of specification as standard on their cars than their European peers but at a similar price point.